Controllable Grid Interface Test System

NREL's controllable grid interface (CGI) test system can reduce certification testing
time and costs while providing system engineers with a better understanding of how
wind turbines, photovoltaic inverters, and energy storage systems react to disturbances
on the electric power system.

The controllable grid interface is the first test facility in the United States that
has fault simulation capabilities. It allows manufacturers and system operators to
conduct the tests required for certification in a controlled laboratory environment.
It is the only system in the world that is fully integrated with two dynamometers
and has the capacity to extend that integration to turbines in the field and to a
matrix of electronic and mechanical storage devicesall of which are within close proximity.

NREL's 7-MVA CGI tests wind turbines offline from the grid, verifies compliance with
standards, and provides grid operators with the performance information they need
for a fraction of the time and cost it would take to test a turbine in the field.
CGI is a unique tool for testing frequency response controls of wind and solar generation
and energy storage. In particular, both inertial and primary frequency response controls
can be tested, validated, and tuned up under real frequency events that can be reproduced
on CGI terminals based on previously recorded data from various power systems or from
data generated by models.